Capacitor TestingCapacitor TestingDefective capacitors are very often the cause of trouble in capacitor-type motors. Shorts, opens, grounds, and insufficient capacity in microfarads are conditions for which capacitors should be tested to determine whether they are good. You can determine a grounded capacitor by setting the instrument on the proper voltage range and connecting it and the capacitor to the line, as shown in Figure 9-17. A full-line-voltage indication on the meter signifies that the capacitor is grounded to the can. A high-resistance ground is evident by a voltage reading that is somewhat below the line voltage. A negligible reading or a reading of no voltage indicates that the capacitor is not grounded.
Mark R. Miller; Rex Miller: Robots and Robotics: Principles, Systems, and Industrial Applications. Capacitor Testing, Chapter (McGraw-Hill Professional, 2017), AccessEngineering